Mechanistic and ecotoxicological studies of amoxicillin removal through anaerobic degradation systems

Raquel Viera Busto*, Joanne Roberts, Colin Hunter, Ania Escudero, Karin Helwig, Lucia Helena Gomes Coelho*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)
241 Downloads (Pure)


Many studies have been conducted on the evaluation and monitoring of micropollutants and by-products in wastewater treatment plants. Considering the increase in the production and consumption of emerging contaminants, such as drugs, personal care products, and plasticisers, it is necessary to conduct studies that support the elaboration of laws and regulations that promote the environmentally sustainable use of sludge and effluents. In this work, the biological degradation of amoxicillin was studied under two anaerobic conditions: i) using a 6 L reactor operated under semi-continuous flow; and ii) a batch system with 100 mL sealed glass syringes. According to the statistical analysis, amoxicillin was completely removed from the systems, but biogas production inhibition was observed (p < 0.05). Liquid chromatography-high-resolution mass spectrometry analysis identified amoxicillin penicilloic acid, amoxilloic acid, amoxicillin diketopiperazine and phenol hydroxypyrazine as by-products under anaerobic conditions. Ecotoxicity tests on effluent treated under the batch conditions showed that the addition of higher amounts of amoxicillin inhibited the target species Aliivibrio fischeri and Raphidocelis subcaptata, causing functional decreases of 28.5% and 22.2% when the antibiotic concentration was 2500 μg L −1. A. fischeri was the most sensitive organism to effluent treated under semi-continuous flow conditions; a continuous reduction in bioluminescence of up to 88.8% was observed after 39 days of feeding, which was associated with by-products accumulation due to unbalanced conditions during anaerobic digestion. Changes in the physico-chemical characteristics of the effluent caused the accumulation and removal of AMX-DKP IV and modified the toxicity to Lactuca sativa and R. subcapitata.

Original languageEnglish
Article number110207
JournalEcotoxicology and Environmental Safety
Early online date4 Feb 2020
Publication statusPublished - 1 Apr 2020


  • pharmaceuticals
  • anaerobic biodegradation
  • Aliivibrio fischeri
  • Lactuca sativa
  • Raphidocelis subcaptata
  • Anaerobic biodegradation
  • Pharmaceuticals

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Pollution
  • Health, Toxicology and Mutagenesis


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